6,326 research outputs found
Biomedical word sense disambiguation with word embeddings
There is a growing need for automatic extraction of information and knowledge from the increasing amount of biomedical and clinical data produced, namely in textual form. Natural language processing comes in this direction, helping in tasks such as information extraction and information retrieval. Word sense disambiguation is an important part of this process, being responsible for assigning the proper concept to an ambiguous term.
In this paper, we present results from machine learning and knowledge-based algorithms applied to biomedical word sense disambiguation. For the supervised machine learning algorithms we used word embeddings, calculated from the full MEDLINE literature database, as global features and compare the results to the use of local unigram and bigram features.
For the knowledge-based method we represented the textual definitions of biomedical concepts from the UMLS database as word embedding vectors, and combined this with concept associations derived from the MeSH term co-occurrences.
Both the machine learning and the knowledge-based results indicate that word embeddings are informative and improve the biomedical word disambiguation accuracy. Applied to the reference MSH WSD data set, our knowledge-based approach achieves 85.1% disambiguation accuracy, which is higher than some previously proposed approaches that do not use machine-learning strategies.publishe
A Semantics-Based Measure of Emoji Similarity
Emoji have grown to become one of the most important forms of communication
on the web. With its widespread use, measuring the similarity of emoji has
become an important problem for contemporary text processing since it lies at
the heart of sentiment analysis, search, and interface design tasks. This paper
presents a comprehensive analysis of the semantic similarity of emoji through
embedding models that are learned over machine-readable emoji meanings in the
EmojiNet knowledge base. Using emoji descriptions, emoji sense labels and emoji
sense definitions, and with different training corpora obtained from Twitter
and Google News, we develop and test multiple embedding models to measure emoji
similarity. To evaluate our work, we create a new dataset called EmoSim508,
which assigns human-annotated semantic similarity scores to a set of 508
carefully selected emoji pairs. After validation with EmoSim508, we present a
real-world use-case of our emoji embedding models using a sentiment analysis
task and show that our models outperform the previous best-performing emoji
embedding model on this task. The EmoSim508 dataset and our emoji embedding
models are publicly released with this paper and can be downloaded from
http://emojinet.knoesis.org/.Comment: This paper is accepted at Web Intelligence 2017 as a full paper, In
2017 IEEE/WIC/ACM International Conference on Web Intelligence (WI). Leipzig,
Germany: ACM, 201
From Word to Sense Embeddings: A Survey on Vector Representations of Meaning
Over the past years, distributed semantic representations have proved to be
effective and flexible keepers of prior knowledge to be integrated into
downstream applications. This survey focuses on the representation of meaning.
We start from the theoretical background behind word vector space models and
highlight one of their major limitations: the meaning conflation deficiency,
which arises from representing a word with all its possible meanings as a
single vector. Then, we explain how this deficiency can be addressed through a
transition from the word level to the more fine-grained level of word senses
(in its broader acceptation) as a method for modelling unambiguous lexical
meaning. We present a comprehensive overview of the wide range of techniques in
the two main branches of sense representation, i.e., unsupervised and
knowledge-based. Finally, this survey covers the main evaluation procedures and
applications for this type of representation, and provides an analysis of four
of its important aspects: interpretability, sense granularity, adaptability to
different domains and compositionality.Comment: 46 pages, 8 figures. Published in Journal of Artificial Intelligence
Researc
Using Multi-Sense Vector Embeddings for Reverse Dictionaries
Popular word embedding methods such as word2vec and GloVe assign a single vector representation to each word, even if a word has multiple distinct meanings. Multi-sense embeddings instead provide different vectors for each sense of a word. However, they typically cannot serve as a drop-in replacement for conventional single-sense embeddings, because the correct sense vector needs to be selected for each word. In this work, we study the effect of multi-sense embeddings on the task of reverse dictionaries. We propose a technique to easily integrate them into an existing neural network architecture using an attention mechanism. Our experiments demonstrate that large improvements can be obtained when employing multi-sense embeddings both in the input sequence as well as for the target representation. An analysis of the sense distributions and of the learned attention is provided as well
Integrating Weakly Supervised Word Sense Disambiguation into Neural Machine Translation
This paper demonstrates that word sense disambiguation (WSD) can improve
neural machine translation (NMT) by widening the source context considered when
modeling the senses of potentially ambiguous words. We first introduce three
adaptive clustering algorithms for WSD, based on k-means, Chinese restaurant
processes, and random walks, which are then applied to large word contexts
represented in a low-rank space and evaluated on SemEval shared-task data. We
then learn word vectors jointly with sense vectors defined by our best WSD
method, within a state-of-the-art NMT system. We show that the concatenation of
these vectors, and the use of a sense selection mechanism based on the weighted
average of sense vectors, outperforms several baselines including sense-aware
ones. This is demonstrated by translation on five language pairs. The
improvements are above one BLEU point over strong NMT baselines, +4% accuracy
over all ambiguous nouns and verbs, or +20% when scored manually over several
challenging words.Comment: To appear in TAC
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